This invention relates to very strong gas mantles and other ceramic structures prepared by a relic-type process which first at least partially pyrolyzes the organic portion of the precursor structure before imbibing the primarily carbon based structure with refractory oxide forming materials.
Light producing mantles have been produced since the 1800s using a simple relic process, i.e., imbibing silk or similar organic fibrous organic structures with metal salts or organometallic compounds and then processing and burning out the organic materials to form ceramic structures. Carl Auer von Wellesbach impregnated yarns woven into sleeves to produce gas light mantles containing thoria and 1 to 2% ceria. When these mantles are heated by a flame they provide a white light source of photons with only a small IR component.
In more recent times (the early 1980s), Goldstein (U.S. Pat. No. 4,793,799) and Nelson (U.S. Pat. No. 4,584,426) developed ytterbia based mantles using somewhat different technologies to produce narrow selected bands of photons in the 980 nanometer (nm) range and also in the 7000 to 10000 nm range. These selected emitters are potentially useful for a number of applications including thermophotovoltaics. The strength of mantles made by these processes have been a problem. In the 1990 several patents have appeared to address the strength issues of photon emitting systems, e.g., U.S. Pat. Nos. 4,776,895, 4,883,619, 4,906,178, 4,975,044, 5,240,407, 5,281,131, 5,356,487, and 5,503,685.
More recently Eva Wong made a major advance in strong ceramic textiles relics and submitted a patent application Ser. No. 08/571,605, entitled "Fibrous Metal Oxide Textiles for Spectral Emitters" filed Dec. 13, 1995. K. C. Chen, filed a patent application Ser. No. 08/645,105 on May 13, 1996 entitled "Method for Making Rare Earth Metal Oxide Ceramic Precursor Compounds and Use Thereof". Dr. Chen prepared organometallic compounds and then spun them in the form of monofilament polymers which are later converted to the oxide structure of very sturdy construction. It is part of this novel invention to use the organometallic compounds prepared by Chen or similarly prepared organometallic compounds to either imbibe pyrolyzed, partially pyrolyzed or normal polymer structure made from such as rayon fibers, sponges, as well as other textiles, and then processing and burning out all of the organic materials to form ceramic structures or to use the organometallic compounds to coat the impregnated porous structure, or to coat a composite component with low emissivity such as alumina fibers.
Currently there are no selective emitter system in wide commercial use other than white light emitters and therefore there is a need for a low cost ceramic emitter systems capable of producing one or more selected bands of radiation.